Ju-Yul Lee

The Factors Influencing on Success of Quitting Smoking in Rural and Urban Smoking Cessation Clinics

The purpose of this paper is to determine an efficient operation plan for a smoking cessation clinic in public health centers. To do so, the primary success factors in smoking cessation have been analyzed after classifying the smoking cessation programs of public health centers into urban and rural areas.

The creation and implementation of the newly implemented Korean Health Education Specialist certification

Professional competencies, standards, and professional preparation of public health professionals, which includes health education and health promotion competencies, is documented in Australia, Europe, Japan, and the United States. Preparing a competent public health education workforce is a newly established priority of the South Korean Ministry of Health and Welfare. In 2010, the first ever Health Education Specialist credential was implemented in South Korea. This commentary describes the creation and implementation of the Health Education Specialist credential and initial workforce preparation outcomes of the new credential.

Signal Analysis for the Condition Monitoring of a Check Valve Using a Time-Frequency Representation

The check valve is one of the important components extensively used in the safety systems in nuclear power plants, and the early detection of its degradation during operation leads to the enhancement of plant safety and availability. The current analysis and diagnostic techniques are based on the spectral information which involves the processing/filtering of signals employing the Fourier Transform (FT). However it is known that this techniques is not effective in analyzing the non-stationary or time-varying signal. In this study a time frequency distribution or representation (TFD or TFR), is explored to represent a noise mixed non-stationary signal coming from the failed check valve onto the time frequency domain. It is better to extract the signature of failures that is useful for the abnormal condition monitoring of check valves. The Wigner-Ville Distribution (WVD) and Exponential Distribution (ED) are examined, which have been successfully used in many other applications such as non-stationary signal detection, time-varying filtering and estimation, etc. In this study the acoustic emission sensors are used to collect the valve failure signal from a test loop, and the collected data is analyzed with the TFR’s. The result shows that the TFR provides additional information for the condition monitoring of the check valves compared to the conventional methods. Introduction The function of a check valve is simply to open and permit flow in only one direction. When the flow stops or is backward, the check valve closes. It is self-actuating, that is, it needs no external power to either open or close. It is a simple component in the process but its failure has a considerable effect to the availability of a plant. In addition, it can cause a degradation of the plant safety when it is used in nuclear power plants[1]. There have been a lot of efforts to develop a technique for the on-line condition monitoring of the check valves in such a plant, since it is inconvenient to repair them during operation. However there is no on-line monitoring device or system for early detection of the performance degradation of the check valve. In the nuclear power plants, what the operators can now do is to disassemble the doubtful valves from the process and to check the integrity during a plant overhaul. This work can also be a cause of failure of check valve. The condition of check valve is generally monitored through the detection and analysis of vibration and/or acoustic signals from the valve body, and an accelerometer and an acoustic emission (AE) sensor are widely used. Then the data collected and analyzed is used for the diagnostic process. The noise mixed signal from the machinery and mechanic components is usually processed with a conventional spectral analysis using the Fourier Transform. The root mean square (rms) value, correlation, coherence, power spectral density (PSD), modified amplitude probability distribution (MAPD) slope, etc. are typical analysis data. But this spectral analysis is in general known to lose a part of the information a temporal variation of the spectral characteristics of a non-stationary signal, because it is assumed that a signal is stationary[2]. Therefore we explored TFR’s WVD and ED, to analyze an AE signal from the valve body in this study. These are well known as a useful tool in dealing with time-varying non-stationary signals. Key Engineering Materials Online: 2004-08-15 ISSN: 1662-9795, Vols. 270-273, pp 209-214 doi:10.4028/www.scientific.net/KEM.270-273.209